In many cutting, spraying and welding operations, plasma arc torches are utilized. With these torches, a plasma gas jet is emitted into the ambient atmosphere at a high temperature. The jets are emitted from a nozzle and, as they leave the nozzle, the jets are highly under-expanded and very focused. However, as the jet leaves the nozzle it begins to expand rapidly. This expansion can greatly reduce the efficiency of the nozzle as the jet energy is lost in the jet expansion, and thus there is a loss of jet thrust and focus. In applications, such as cutting and welding, this expansion can diminish the quality and process speeds, especially in cutting operations. Further, the shape of the nozzle throat can cause arc instability, which further diminishes performance. Therefore, improved nozzle performance is desirable.
Further limitations and disadvantages of conventional, traditional, and proposed approaches will become apparent to one of skill in the art, through comparison of such approaches with embodiments of the present invention as set forth in the remainder of the present application with reference to the drawings.